Manama, Bahrain: The close proximity of civil unrest and danger in Bahrain was made clear to the Force India Formula One team on Wednesday night when a firebomb exploded as they returned from the Sakhir circuit to their hotel.

The incident happened as the vehicle was stuck in a traffic jam, Bahrain International Circuit chairman Zayed R Alzayani said.

Nobody was injured, but one member of the team, based at Silverstone in England, decided afterwards to leave Bahrain and return home.

The four mechanics, who were in a hire car, were accidentally caught up in a clash between protesters and police on the main motorway from Manama to the circuit at Sakhir, Alzayani said.

The four in the car returned safely to their hotel and they decided to stay on. The team member going home was not involved.

Alzayani played down the matter, and said he would not request any tighter security as a result.

"It was an isolated incident - and my wife was involved too," he said.

"The protestors were not targeting the cars, they just happened to be there. Nobody was injured.

"I don't command the police. They know what to do better than I do. I have a race to run."

The blast happened when the traffic came to a halt and a 'Molotov cocktail' exploded near their car.

The Force India incident came despite prolonged assurances from the sport's ruling body, the International Motoring Federation (FIA) and Formula One's chief executive and commercial ringmaster Bernie Ecclestone that the Gulf state is a completely safe place to host this weekend's race.

The blast took place about 20 minutes car ride from the circuit on the outskirts of the capital Manama at the end of a first day's work for the teams in Bahrain.

They flew in on Monday following last Sunday's Chinese Grand Prix to be greeted by a comprehensive demonstration of security forces with vehicles parked at intervals on all main roads and around the circuit.

Squads of officers have patrolled the paddock and the circuit throughout the week while the teams have arrived to prepare for the event.

Many of the teams and their drivers are known to have private misgivings about the wisdom of racing in Bahrain amid ongoing civil unrest, but none have so far publicly questioned the decision.

Last year's race was cancelled due to the unrest that reportedly claimed more than 40 lives.